Method for producing regenerative hydrocarbons via the methanol route and corresponding synthesis plant

Abstract

The invention relates to a method for producing hydrocarbons. The method comprises the steps of providing i) a regenerative starting material (5) containing carbon (C) and hydrogen (H). Furthermore, the method comprises gasifying ii) the starting material (5) in a gasifier (8), wherein a synthesis gas (6) is produced, producing iii) methanol (MeOH) from the synthesis gas (6) and regenerative hydrogen (H2), wherein pure methanol (16) is separated from the produced methanol product gas (10), and producing iv) a hydrocarbon (CH) from the pure methanol (16), wherein the pure methanol (16) is catalytically converted into a hydrocarbon target product (31), in particular kerosene, gasoline, diesel or naphtha, wherein by-products (17, 23, 24, 32, 33) of the methanol synthesis and / or hydrocarbon synthesis are returned to the gasifier (8) and are further reacted into synthesis gas (6) which is then also converted into methanol and the hydrocarbon product (31). The invention also relates to a corresponding synthesis plant.

Description

[0001] Description

[0002] Process for producing renewable hydrocarbons via the methanol route and corresponding synthesis plant

[0003] The present invention relates to a method for producing hydrocarbons and a corresponding synthesis plant, wherein in particular an integrated use of a gasifier for synthesis gas production and by-product utilization in a process for producing regenerative hydrocarbon fuels via the methanol route is proposed.

[0004] The invention aims at a significantly improved synthesis of renewable hydrocarbons, which are to be used in particular as fuels (for example, kerosene, gasoline, or diesel). A special role in this context is also played by the synthesis of renewable hydrocarbons that can be used as synthesis building blocks in the chemical industry; synthetically produced olefins, for example, are suitable for this purpose.

[0005] The invention relates in particular to the so-called methanol route, in which methanol is first produced from renewable starting materials and then converted into hydrocarbon products. The methanol route is considered advantageous among the possible technologies for hydrocarbon synthesis, among other things because the upgrading of the primarily synthesized hydrocarbon products to the end products is relatively simple and cost-effective. In contrast, Fischer-Tropsch synthesis (FT synthesis) requires extensive refinery processes to convert the directly obtained primary product ("syncrude") into the end products. The main reasons for this are the narrower chain length distribution of the primary products produced via the MeOH route and their significantly higher degree of isomerization. Both properties typically correspond to the properties required for the end products (such as kerosene).Only a saturation of double bonds by mild hydrogenation is necessary.

[0006] In contrast, "FT syncrudes" must be treated by complex "hydrocracking" with attached separation processes and extensive recirculation in order to achieve the required chain lengths and degrees of isomerization.

[0007] The general challenge in the production of renewable hydrocarbons—including the MeOH route—is that renewable hydrogen and renewable carbonaceous starting materials must be used as reactants. The production or provision of these reactants is very energy- and cost-intensive according to the current state of the art. Carbon dioxide (CO2), for example, can be produced quite cost-intensively by direct air capture (DAC), and hydrogen (H2) by water electrolysis. As a result, the production costs of renewable hydrocarbons are currently several times higher than the costs for producing the same end products from fossil raw materials.

[0008] The processes for producing renewable methanol are still in the development stage, although the scale-up from pilot and demonstration scale to production scale has already begun. Initial implementations producing renewable MeOH from CO2 and hydrogen have been reported in Iceland and Chile, respectively. However, the use of CO2 as a carbon source is associated with a fundamental disadvantage, which is described in more detail below.

[0009] Furthermore, it must be considered that every chemical synthesis inherently leads to the formation of undesirable byproducts that are either impossible or very difficult to market. Currently, there is a lack of a technically and economically advantageous technology for the utilization of these byproducts, combined with a cost-effective supply of renewable starting materials.

[0010] A process and a plant for producing hydrocarbons is known, for example, from WO 2022 / 228793 Al.

[0011] A fundamental disadvantage of using renewable CO2 as a carbon source according to the state of the art is that the conversion to methanol (MeOH) to the hydrocarbon end products requires large quantities of expensive electrolysis hydrogen, as can be seen from the following equations:

[0012] CO2 + 3H2CH3OH + H2O and n CH3OH - (CH2) n - + nH20 (1)

[0013] Here, -(CH2)- stands for the methylene unit linked in hydrocarbon chains. The high H2 demand for MeOH synthesis (three molar equivalents based on the CO2 used) is due to the high oxygen content in carbon dioxide.

[0014] However, the production of methanol and subsequently of hydrocarbons from carbon monoxide (CO) is more economical, as the following equations show; here only two molar equivalents are required based on the CO used:

[0015] CO + 2H2CH3OH and n CH3OH - (CH2) n - + n H2O (2)

[0016] The state-of-the-art processes used to produce renewable hydrocarbons use either CO2 from the air (DAC) or from exhaust gases or flue gases, which arise, for example, from the combustion of biomass with air or oxygen. The increased demand for expensive electrolysis hydrogen according to equation (1) is accepted. The conversion of CO2 to carbon monoxide (CO) by the so-called reverse water gas shift reaction (RWGS), followed by MeOH synthesis from CO according to equation (2), which is possible in principle, offers no advantage because RWGS itself requires the use of hydrogen (CO2 + H2CO + H20). Furthermore, RWGS technology is not yet mature.

[0017] One possibility not yet exploited with regard to the large-scale synthesis of renewable hydrocarbons is the gasification of biomass with mixtures of oxygen and steam, producing a synthesis gas which contains proportions of CO2 but also CO and hydrogen.

[0018] In addition to the previously described provision of the regenerative carbon and hydrogen building blocks required for the synthesis, the invention addresses the aspect of the formation of undesirable synthesis by-products and aims at their inventive utilization possibilities. The competitive production of regenerative products requires that the introduced regenerative resource building blocks and the energy used be utilized as fully as possible in order to be efficient and thus economical. This requirement is not met, or only inadequately met, by conventional processes.

[0019] For example, the energy-rich oxygen produced as a by-product in water electrolysis is not used, or only to a limited extent, in conventional processes for producing renewable hydrocarbons. A further disadvantage of state-of-the-art processes is that no technologies are available for utilizing the by-products of methanol synthesis and the associated hydrocarbon synthesis, or that only technically or economically immature ones are available.

[0020] The creation of by-products necessitates their simultaneous marketing with the main products, which is often not possible due to market demand. Consequently, thermal utilization remains the only option, which typically cannot cover the manufacturing costs of renewable products.

[0021] In summary, it should be noted that the methanol route, which, as described, is even significantly more selective than alternative routes, e.g. FT technology, must be further improved technically and economically in the future in order to reduce the manufacturing costs of renewable products.

[0022] However, significant progress can be achieved through the improved technology presented for the provision of renewable raw materials and an advantageous method for the utilization of by-products.

[0023] It is therefore an object of the present invention to provide means which make it possible to solve the problems mentioned and in particular to utilize the by-products optimally or (almost) completely and thus to significantly improve the technology for the synthesis of hydrocarbons, in particular via the methanol route, technologically and economically.

[0024] This problem is solved by the subject matter of the independent patent claims. Advantageous embodiments are the subject matter of the dependent patent claims.

[0025] One aspect of the present invention relates to a process for producing hydrocarbons, preferably regenerative hydrocarbon-based fuels, via the methanol route. The process comprises providing and / or feeding a regenerative feedstock containing carbon (C) and hydrogen (H) to a gasifier, preferably a fluidized-bed gasifier. Additionally, the feedstock may contain oxygen (O2).

[0026] The process also includes gasification of the

[0027] Starting material or starting substance in a gasifier, producing a synthesis gas. In other words, the starting material can be conveniently fed to the gasifier via appropriate means. Furthermore, a gasification reaction in the gasifier, particularly using oxygen and / or water as the gasification agent, is advantageously designed to be exothermic, for example, at temperatures around 900 °C.

[0028] The said synthesis gas may in particular comprise hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4) and / or ethene (C2H4).

[0029] The process further comprises the production or synthesis of methanol from the synthesis gas and regenerative, i.e. preferably green, hydrogen, wherein pure methanol is separated or separated from the methanol product gas produced in the corresponding reactor.

[0030] The hydrogen is preferably provided electrolytically, in particular via a (polymer electrolyte membrane) PEM water electrolysis in a highly pure form.

[0031] In addition, the process includes the production or

[0032] Synthesizing a hydrocarbon from pure methanol, wherein the pure methanol is catalytically converted into a

[0033] hydrocarbon target product, in particular kerosene, gasoline, diesel or naphtha (as end product).

[0034] According to the process, by-products and off-gases from methanol synthesis and / or hydrocarbon synthesis are separated, in particular from the main or pure products, returned to the gasifier and further converted to synthesis gas, whereby the synthesis gas is then also converted into methanol and the hydrocarbon product. The by-products mentioned can be off-gases from the synthesis of methanol (MeOH) and hydrocarbon synthesis, in particular CI and C2 hydrocarbons, small amounts of MeOH and other so-called "oxygenates" as well as residues of unreacted carbon monoxide (CO), carbon dioxide (CO2), hydrogen (H2), LPG (liquefied petroleum gas), C3 / C4 carbon components and other hydrocarbon by-products.

[0035] The recycling process according to the invention offers significant advantages overall compared to a design in which, for example, hydrogen components are discharged unused. In particular, it solves a transport and procurement problem for renewable starting materials, since these starting materials would otherwise have to be procured in a complicated and expensive manner and made accessible to the corresponding synthesis process.

[0036] In one embodiment, the carbon- and hydrogen-containing feedstock comprises biomass, flue gas, and / or waste, or consists of each of these. This makes it particularly advantageous to provide a feedstock that is suitably comparably blended for gasification, methanol synthesis, and hydrocarbon synthesis, which can also be obtained and provided in a cost-effective and simple (climate-friendly) regenerative manner.

[0037] In one embodiment, the gasifier comprises a fluidized bed and a circulating fluidized bed with solid particles which can be circulated preferably between a first fluidized bed (gasifier) ​​and a further, second fluidized bed (combustion), preferably comprising a combustion reactor.

[0038] In one embodiment of the gasifier or the gasification process, the gasification of the starting material comprises an (endothermic) reaction of the same with water vapor in the fluidized bed and combustion - preferably in the described combustion reactor - by oxidation with oxygen. In one embodiment of the invention, a corresponding combustion exhaust gas from the combustion can be reintroduced into the fluidized bed together with the starting material, whereby in particular a circulation or cycle in the gasifier can be maintained.

[0039] In a further embodiment, the described by-products are then made accessible for combustion.

[0040] This alternative to a conventional gasification reaction (gasification operation) advantageously allows the actual gasifier to be operated solely with steam (without oxygen), thereby advantageously preventing excessive oxidation, for example of carbon monoxide. Furthermore, the previously described embodiments are advantageous for the efficient conversion of by-products, as well as for a continuous process for methanol synthesis and the production of renewable hydrocarbons.

[0041] According to one embodiment, a gasification agent, in particular water and / or oxygen, can be continuously fed to the gasifier together with the starting material containing carbon, hydrogen (and optionally oxygen). This continuous feed is favorable, practical, and cost-effective for the synthesis process as a whole.

[0042] According to one embodiment, the regenerative hydrogen originates from water electrolysis, in particular PEM water electrolysis, or is provided accordingly. As an alternative to PEM water electrolysis, it is also possible to provide the hydrogen via alkaline water electrolysis. In one embodiment, the (regenerative) hydrogen obtained in this way is then reacted with the synthesis gas via methanol synthesis, with a mass flow of the electrolytically obtained regenerative hydrogen preferably being selected depending on how much hydrogen is already present in the synthesis gas. This embodiment also makes it possible to adapt the starting elements in the starting material to the subsequent process steps in such a way that as many by-products as possible are utilized and the synthesis as a whole can be carried out as efficiently and cost-effectively as possible.

[0043] In one embodiment, a portion of the oxygen also produced during electrolysis is fed into the gasification process. This allows, in particular, the heat management of the gasification process to be advantageously regulated and controlled. In addition, the added oxygen can promote the conversion of the other components of the starting material in the subsequent process steps, resulting in a high target hydrocarbon yield.

[0044] In one embodiment, the methanol product gas contains foreign gases, water and unreacted components of the synthesis gas.

[0045] In one embodiment, liquid or condensed methanol and water components are separated from gases in a separator and these gases are also returned (as recycle gas) to the methanol synthesis or to a corresponding methanol reactor.

[0046] In a further embodiment, the components or constituents condensed in the separator are fed to a distillation in which raw water and pure methanol are obtained, the raw water being fed to a water treatment or water purification or deionization process so that, after purification, the water can be fed back to the electrolysis and / or to the gasifier as a gasification agent. Advantageously, the vast majority of the water purified by the water treatment unit can be fed back to the electrolysis and the gasifier, creating a beneficial water cycle. This use of the treated water is particularly advantageous because it is ion-free water. Unlike fresh water, which can be fed into the process from outside, this does not have to be deionized, which results in an economic advantage.The described water cycle is particularly interesting when the invention is applied in water-scarce countries, for example those that are predestined as locations for PtX (Power-to-X) plants, because in these countries inexpensive renewable electricity is usually available ( e . g . in desert regions through photovoltaics and wind energy ).

[0047] According to a further embodiment, the pure methanol is (additionally) separated by condensation, with any low-boiling components present, particularly methane, remaining in gaseous form and also being fed into the gasification process to form synthesis gas. In other words, this provides a particularly advantageous utilization option for these low-boiling components formed as by-products. Thus, a process cycle is closed again via gasification, which significantly reduces or completely eliminates the overall waste of the process, while advantageously increasing the hydrocarbon yield.

[0048] In one embodiment, water (raw water) is also produced as a product of hydrocarbon production, which is separated and fed to the water treatment plant, as well as liquid hydrocarbons and gaseous hydrocarbons, which are fed back into the hydrocarbon synthesis as cycle gas. These hydrocarbons contain, for example, C1 to C4 carbons as their main components, which have a high proportion of oligomerizable olefins. In order to prevent an accumulation of individual components that cannot be oligomerized or utilized in the reactor (e.g. methane), a portion of the resulting cycle gas containing hydrocarbon (HC) is removed from the cycle. This removed mass flow is also advantageously not "lost" from the overall process, but is fed to the gasifier as a further mass flow to be converted back into synthesis gas.The advantages described above apply analogously here.

[0049] Furthermore, according to one embodiment, the liquid hydrocarbons produced during hydrocarbon synthesis are fed to a separation column in which further gaseous components or fractions are dissolved or separated, which are also fed to the gasification to form synthesis gas. This advantageously also enables the comprehensive utilization of the by-products for the gasification or the subsequent synthesis steps.

[0050] The recycling of by-products described here according to various designs benefits overall the resource-efficient and cost-effective production of hydrocarbons.

[0051] The liquid components or fractions can then be fed into a hydrogenation unit. In such a hydrogenation reactor or several hydrogenation reactors, saturation of the double bonds and, optionally, cleavage of aromatic hydrocarbons then occur.

[0052] A product of the hydrogenation or hydrogenation unit can be further fed to a fractionation unit, which can consist of one or more additional separation columns. The purpose of this fractionation unit is to separate the target product or end product of the hydrocarbon synthesis. The target product is preferably kerosene with carbon fractions or valences (C number) in the range of 10 to 20. Alternatively, gasoline, diesel, or naphtha can be obtained as the target product.

[0053] As described, a lighter portion of the hydrocarbons separated in the fractionation unit can, in one embodiment, be fed entirely to the gasification process, where a suitable conversion to synthesis gas takes place. The other components were preferably separated and recycled beforehand, as indicated, but such hydrocarbons (C1 to C4) can be regenerated during the hydrogenation process, necessitating a further separation.

[0054] The high boilers isolated in the separation unit or column mentioned above - preferably these are hydrocarbons with carbon contents (C numbers) above 20 - are also converted into the final product by, in one embodiment, first being fed to the gasifier, where they are converted into synthesis gas, which is then fed back to the MeOH and HC synthesis (hydrocarbon synthesis).

[0055] In a further embodiment, a synthesis gas stream for methanol synthesis comprises, for example, carbon monoxide and hydrogen, as well as carbon dioxide (CO2). The carbon dioxide can be removed, for example, via CO2 capture and returned to the gasifier as a seal gas or used therein. This seal gas prevents, in particular, the penetration of air into the gasifier, for example, in the fuel supply area.

[0056] In the synthesis gas stream, a methane concentration (CH4) is advantageously measured and monitored online as a characteristic parameter. In addition, concentrations of (elemental) carbon, hydrogen, and oxygen can be measured in order to adjust or readjust the mass flows of the gasification agents (water and oxygen) to be added.

[0057] According to an advantageous embodiment, the process according to the invention makes it possible, in particular, to reduce the hydrogen requirement by 50%, in contrast to hydrocarbon synthesis, in which only electrolytically obtained hydrogen is used as the reactant. Through the described multiple gasifier recycling of the resulting by-products, i.e., with complete by-product utilization, it is even possible to reduce the quantity of the previously expensive regenerative hydrogen by 60 to 70%.

[0058] A further aspect of the present invention relates to a synthesis plant which is designed to carry out the process described here.

[0059] The plant advantageously comprises the gasifier, a corresponding methanol reactor for methanol synthesis, and a hydrocarbon synthesis facility. Furthermore, the plant further comprises means that allow the byproducts of methanol synthesis and the byproducts of hydrocarbon synthesis (as described) to be recycled to the gasifier and converted into synthesis gas, which can then be converted into methanol and the hydrocarbon product.

[0060] The system according to the invention makes it possible, in particular, to supply the gasifier with further products or reactants in addition to the conventionally available input materials, such as solid fuels, water, and oxygen. These further substances can be supplied, premixed, and / or injected via recirculation means, such as supply lances and / or corresponding pumps, wherein the lances are furthermore expediently arranged in such a way that the fluid dynamics of the fluidized beds typically present in gasifiers are supported for efficient gasification. The path of these further substances is described in more detail as mass flows in the specific embodiments described below.

[0061] In other words, the utilization of MeOH by-products and off-gases from hydrocarbon synthesis can be accomplished in a particularly advantageous manner according to the invention in the same apparatus in which the synthesis gas is also provided. This then results in a single process-engineering apparatus for the production of the synthesis gas and the corresponding by-product utilization. In the context of corresponding industrial plants, this "gasifier integration" according to the invention represents a significant simplification in terms of investment and operating costs. Furthermore, in addition to the advantages described above, synergies arise in the heat management of the entire plant.

[0062] In one embodiment, the synthesis plant further comprises a heat transfer system configured to supply heat to sub-steps of the process according to a specific heat requirement. This heat can, in particular, be provided entirely by exothermic process steps, with the heat transfer system being, for example, a multi-stage steam system and / or a molten salt system.

[0063] Embodiments, features and / or advantages which relate to the manufacturing process in the present case also directly concern the synthesis plant and vice versa.

[0064] The term "and / or" or "respectively" as used herein, when used in a series of two or more elements, means that any one of the listed elements may be used alone, or any combination of two or more of the listed elements may be used. Further details of the invention are described below with reference to the figures.

[0065] Figure 1 shows essential process steps using a simple schematic flow chart.

[0066] Figure 2 shows, using a detailed flow diagram, method steps according to the invention and system components according to the invention with a large number of advantageous embodiments of the presented inventive solution.

[0067] Figure 3 uses a simplified flow diagram to illustrate heat profiles of plant components and possible advantages in heat management and heat recovery within the synthesis plant according to the invention.

[0068] Figure 4 further indicates a simplified flow diagram of a specific embodiment of the operation of the carburetor as part of the inventive idea.

[0069] In the exemplary embodiments and figures, identical or equivalent elements may be provided with the same reference numerals. The illustrated elements and their relative sizes are generally not to scale; rather, individual elements may be exaggeratedly thick or oversized for clarity and / or clarity.

[0070] The present invention provides a particularly efficient combination of an improved technology for providing regenerative starting materials and an advantageous method for utilizing synthesis by-products.

[0071] The provision of the regenerative carbon and hydrogen components in the form of a synthesis gas is achieved through a combination of gasification and (regenerative), preferably electrolytic, hydrogen production.

[0072] It is noteworthy that, compared to the state of the art, a significantly smaller amount of electrolysis hydrogen is required.

[0073] The required quantity is calculated from the H2 requirement for the conversion of the carbon components (CO and some CO2) to methanol (MeOH), less the amount of H2 that is already formed in the gasifier (see reference numeral 8 below) and is thus available for the conversion of the C components.

[0074] The respective stoichiometry of gasification depends on the individual composition (CHO ratios) of the renewable feedstocks used, be it biomass, flue gas, waste, or garbage. Furthermore, the ratio of the gasification agents, particularly oxygen (O2) and / or water (H2O), influences the gasification process and its stoichiometric conversion. However, a rough qualitative reaction equation for gasification can be given as follows, depending on the type of input and output materials:

[0075] Regenerative CHO substances + water + oxygen CO / CO2 / H2 / H2O mixtures (3)

[0076] If these CO / CO2 / H2 / H2O mixtures ("synthesis gas") are converted into renewable methanol, significantly less additional electrolysis hydrogen is required than in the conventional process according to equation 1 described above.

[0077] In the best case, significant amounts of H2 are already present in the gasification product, and the carbon is present almost exclusively in the form of carbon monoxide (CO) (possibly only minimally in the form of CO2). In this case, even less than two molar equivalents of hydrogen per mole of carbon component must be generated electrolytically to convert the carbon components into methanol.

[0078] The described gasification of carbon-containing regenerative starting materials represents one area of ​​the invention. Furthermore, a particularly efficient utilization of the by-products is proposed. These are exhaust gases and / or by-products from MeOH and hydrocarbon syntheses (Cl- / C2 hydrocarbons, small amounts of MeOH and other oxygenates, as well as residues of unconverted CO, CO2, H2), LPG, C3 / C4 components, and other hydrocarbon by-products.

[0079] These substances are first separated from the main products and then returned to the gasifier, which—in addition to the biomass feedstock—is equipped with appropriate feed devices for liquids and gases. There, they are converted into synthesis gas, which is subsequently converted into MeOH and finally into the hydrocarbon end products.

[0080] In the foreseeable future, demand will be particularly high for renewable kerosene as the preferred hydrocarbon end product. Unlike "orange gas," LPG, and possibly naphtha, this will be quite easy to market.

[0081] In the ideal case, according to the invention, only the main hydrocarbon product, e.g. kerosene, leaves the process in addition to unused electrolysis oxygen, while the water also formed during the synthesis is purified and returned to the electrolysis where it is converted into hydrogen and oxygen (cf. description of Figure 2 in detail below).

[0082] Ideally, no (poorly marketable) hydrocarbons and no (unconverted) valuable intermediate components such as CO, CO2, and H2 leave the overall process. The byproducts are recycled back into the process without the need for additional processing equipment and ultimately converted into the main product. This utilization is of great importance, as methanol and hydrocarbon synthesis typically primarily produces a byproduct proportion of around 20 wt.%. According to the invention, this can be converted into the main product without additional processing equipment, resulting, among other things, in enormous economic advantages. The process steps are described in detail using the following equations:

[0083] For gasification: Regenerative CHO materials + water + oxygen CO / CO2 / H2 / H2O mixtures (3)

[0084] For MeOH synthesis: CO / CO2 / Hz / HzO + electrolysis-Hz - CH3OH + residual water (4)

[0085] For hydrocarbon synthesis: CH3OH - (GHz)- + water + by-products (5)

[0086] For electrolysis: Water + residual water Electrolysis-H2+ Oxygen

[0087] The by-product utilization in the gasifier (runs there together with reaction (3)):

[0088] By-products + water + oxygen CO / -CO2 / H2 / H2O mix (from recycling) (3b)

[0089] The MeOH synthesis from the recycling products takes place together with reaction (4) in the same reactor: CO / CO2 / H2 / H2O mix by recycling + additional electrolysis-H2-additional CH3OH + additional water (4b)

[0090] The hydrocarbon synthesis from the additional MeOH proceeds with reaction (5) in the same reactor; the following applies here: Additional CH3OH Additional - (CH2)- + Additional water + Additional by-products (5b)

[0091] Summa summarum, ie when all equations are added together and the intermediate products that are converted again (such as electrolysis hydrogen or the by-products) are canceled out, the sum equation is:

[0092] Regenerative CHO substances -(CH2)- (main product) + residual O2 (+ excess water).

[0093] This shows that all of the carbon from the starting materials is found in the final product after conversion. The hydrogen introduced with the renewable starting materials or generated through electrolysis is also largely present in the main product; although only a small portion can leave the process in the form of excess water.

[0094] In this regard, it should be noted that some of the partial reactions produce water, with a large portion of this water being converted back into electrolysis. The amount of excess water depends quantitatively on the water content of the renewable hydrogen, carbon, and optionally oxygen-containing (CHO) starting material 5. Biomass can contain significant amounts of water, whereas the water content of garbage or waste is generally lower.

[0095] The process can also provide some additional oxygen, as not all of the electrolysis oxygen is expected to be needed for gasification.

[0096] Unlike the ideal case presented, certain deviations will occur in reality, e.g., due to impurities contained in the feedstock. Biomass contains small amounts of nitrogen (N) and other elements, which typically have to be removed via small wastewater streams ("purges"). These streams can lead to a slight reduction in the main product yield, the extent of which depends on the proportion of impurities in the feedstock and the efficiency and selectivity of the processes used to separate these streams.

[0097] Figure 1 only outlines the main process steps of the process according to the invention. The process according to the invention is a process for producing hydrocarbons (CH), comprising i) providing the regenerative starting material 5 containing carbon (C) and hydrogen (H).

[0098] Under ii), the process further comprises gasifying the starting material 5 in the gasifier 8, whereby a synthesis gas 6 is produced.

[0099] Under iii) the process further comprises producing methanol from the synthesis gas 6 and regenerative hydrogen (H2), wherein pure methanol 16 is produced from the

[0100] Methanol product gas 10 is separated.

[0101] Under iv), the process further comprises producing a hydrocarbon from the pure methanol 16, wherein the pure methanol 16 is catalytically converted into a hydrocarbon target product 31, in particular kerosene, gasoline, diesel or naphtha.

[0102] The process is further characterized in that by-products (cf. 17, 23, 24, 32, 33 based on Figure 2) of the methanol synthesis and / or the hydrocarbon synthesis are recycled to the gasifier 8 and further converted to synthesis gas 6, which is then also converted into methanol and the hydrocarbon product 31.

[0103] An embodiment of the process according to the invention is described in more detail below with reference to Figure 2. The process is described in particular with reference to a synthesis plant 50 according to the invention.

[0104] A fresh water stream 1 is fed to a water treatment plant 29 in which deionization and depletion of organic components takes place, whereby the resulting pure water streams 2a and 2b are made available for the water electrolysis (here marked "PEM") and the gasifier 8. The water stream 2a for the electrolysis can even be ultrapure water.

[0105] The gasifier 8 is further supplied with oxygen 4 from the electrolysis and the regenerative C, H, O-containing starting material 5 (e.g. biomass, waste and / or flue gas). The synthesis gas 6 produced in this way contains in particular CO, H2 and CO2, but also some water vapor and possible foreign components such as nitrogen N2. The synthesis gas is converted in the MeOH reactor 9 with additional hydrogen 3a from the electrolysis, the mass flow of which depends in particular on how much H2 is already in the synthesis gas stream 6 and how high the total H2 requirement for the conversion of CO and CO2 is.

[0106] The MeOH reactor product gas 10 produced contains, among other things, the foreign gases, water, and unreacted components of the synthesis gas. After cooling, the condensed liquid components (methanol and water) are separated from the gases in a separator.

[0107] The gases are then returned to the reactor as recycle gas 12, although under certain circumstances a portion may have to be discharged. The amount of this discharge stream is preferably calculated such that the foreign atoms introduced into the process per unit of time are discharged again in the same unit of time, thus preventing accumulation. As much of the hydrogen as possible is removed from the discharge stream, in particular by a so-called "pressure swing adsorption" (cf. reference numeral 35 in Figure 2), before the discharge stream 14 finally leaves the process. The separated hydrogen 13 is returned to the MeOH reactor, where the hydrogen is (re)converted.

[0108] The above-mentioned condensed reactor products, methanol and water, which are separated in a separator 15 as stream 11, are fed to a MeOH distillation 18, where raw water 7a and pure methanol 16 are obtained.

[0109] A small part of the pure methanol is returned to the distillation column as reflux (see arrow pointing to the left), while the majority is fed to the hydrocarbon synthesis CH ((KW) synthesis).

[0110] The raw water 7a, which may contain small amounts of MeOH and other organic components, is fed to the aforementioned water treatment 29 so that the water, after purification, is made available again for electrolysis or gasification.

[0111] During the separation of pure methanol 16, any low-boiling components present, e.g., traces of methane formed, remain gaseous due to condensation (further separation in the condenser 19). These uncondensed low-boiling components 17 consist largely of the elements C, H, and O; therefore, gasification to form synthesis gas represents an ideal utilization option. Stream 17 is fed to the gasifier.

[0112] The pure methanol 16 fed to the hydrocarbon synthesis, which may contain residual water depending on the column operation (separation process), is catalytically converted into hydrocarbons, preferably kerosene, or gasoline, diesel, or naphtha. The hydrocarbon synthesis block can also consist of a combination of the "methanol-to-olefins" (MtO) process with subsequent olefin oligomerization and / or gasoline synthesis ("methanol-to-gasoline").

[0113] The mixture of the hydrocarbons 20 formed, with water as a co-product, is further fed to a separator 26, which separates the water, the liquid and the gaseous hydrocarbons from each other.

[0114] The raw water 7b, which may contain traces of hydrocarbons, is fed to the purification stage 29.

[0115] The stream of liquid hydrocarbons (HC) 21 is fed to the HC separation 27 (e.g. distillation), while the gaseous hydrocarbons 22 (main components C1 to C4), which have a high proportion of oligomerizable olefins, can be advantageously and efficiently returned to the HC synthesis as cycle gas 22.

[0116] To prevent the accumulation of individual components that cannot be oligomerized or converted in the reactor (e.g., methane), a portion of the hydrocarbon cycle gas 22 can be removed from the cycle. However, according to the invention, this exhaust gas from the hydrocarbon synthesis, stream 23, is not lost from the process; rather, this stream 23 is also fed to the gasifier 8 to be converted back into synthesis gas.

[0117] The stream of liquid hydrocarbons 21 is fed to the separation unit 27 for hydrocarbon separation. The separation unit 27 may consist of one or more separation columns. In this unit 27, the fraction of gaseous hydrocarbons 24 dissolved in mass stream 21 is separated from the stream of liquid hydrocarbons 25 (stream 24 typically contains hydrocarbons with C numbers 1 to 4).

[0118] The gaseous hydrocarbons 24 are also fed to the gasifier 8 and converted into synthesis gas 6, while the stream of liquid hydrocarbons 25 is fed to a hydrogenation unit 30. There, in one or more hydrogenation reactors, saturation of the double bonds and optionally splitting of aromatic hydrocarbon rings takes place. The product of the hydrogenation unit 30 is fed to a fractionation unit 28, which consists of one (further) separation column or several separation columns. The purpose of this fractionation unit is to separate the target product 31, for example kerosene with C numbers in the range from 10 to 20.

[0119] The lighter fraction 32 of the hydrocarbons separated in the fractionation unit 28 (in the above example C1 to C9) can advantageously be profitably fed back completely to the gasifier 8, where it is converted into the corresponding synthesis gas 6.

[0120] The carbon components C1 to C4 were previously separated and recycled, as described above. However, such hydrocarbons can be regenerated during the hydrogenation process, allowing a further, analogous separation.

[0121] Optionally, the low-boiling components can also be removed from the separation unit 28 in the form of several fractions. For example, a naphtha side fraction 34 containing C5 to C9 can be removed as a marketable by-product, so that only the remaining low-boiling components C1 to C4 are returned to the gasifier 8.

[0122] The high boilers 33 isolated in the separation unit 28, in the above example the hydrocarbons with C numbers above 20, are advantageously also converted into the end product 31 by first being fed to the gasifier 8 according to the invention, where they are converted into synthesis gas 6, which is then in turn fed to the MeOH and HC synthesis.

[0123] The described process enables an almost complete conversion of the carbon contained in the CHO starting material 5 into the target product 31 , for example in the form of renewable kerosene, possibly only apart from the discharge stream 14, from which the valuable hydrogen was largely removed before discharge.

[0124] Optionally, further by-product fractions, such as gasoline or diesel, can be obtained (see mass flow 34) if by-product marketing appears to be appropriate.

[0125] The water also produced during the synthesis is purified and largely returned to the process. Depending on how much water was introduced into the process with the starting material 5, some of the water may be produced as an excess by-product. Furthermore, the portion of the electrolysis oxygen not converted in the gasifier 8 remains as a by-product or can be used profitably in another way.

[0126] Figure 3 outlines, using a special flow diagram, heat profiles of system components and a heat management system possible according to the invention, in particular heat recirculation within the synthesis system 50. Heat profiles or thermal flows (each from the higher to the lower temperature level) are indicated in Figure 3 by the flow arrows.

[0127] The described overall process includes both exothermic reactions and subprocesses that require additional heat. Gasifier 8 can be operated exothermically by adding sufficient amounts of oxygen. A favorable temperature level is around 900 °C. The synthesis reactions (see 9, CH, and 30 for methanol and hydrocarbon synthesis, as well as hydrogenation) are also exothermic.

[0128] The heating and evaporation processes, however, require (endothermic) heat (see 18, 27, and 28). Heat must be provided at the required temperature level for the starting materials 5 fed into the reactors and for the mixtures evaporating in the column bottoms.

[0129] According to the invention, the sub-steps requiring heat are supplied with heat via a heat transfer system 51, which is advantageously provided by the exothermic steps.

[0130] The heat transfer system 51 can be a multi-stage steam system; in addition, a molten salt system can be implemented, particularly in the case of high temperatures above 300°C.

[0131] The heating of the starting materials flowing into the reactors (not shown) can be carried out by direct heat transfer from the reaction products heated by reaction to the cooler incoming starting materials, whereby a heat exchanger can be used in each case.

[0132] Due to the exothermic nature of all reactions, the overall process advantageously has a heat surplus (cf. reference numeral 52), with the waste heat from the electrolysis REM also being added. The heat surplus 52 can be used to heat external processes. As described above, the synthesis gas required for the synthesis is produced within the process according to the invention with the aid of a gasifier 8. Depending on the type of gasifier and the fuel used, it is possible that the gasifier must be continuously supplied with a so-called seal gas 40 (cf. Figure 2). This seal gas 40 prevents in particular the penetration of air into the gasifier 8, for example in the area of ​​the fuel or biomass feed, by applying a slight seal gas overpressure. The continuous outflow of small amounts of the pressurized seal gas 40 also advantageously prevents air from penetrating the gasifier.

[0133] Suitable barrier gases are gases that are non-flammable for safety reasons and ideally are already present in the process, thus ensuring that their presence does not interfere with the process. Therefore, the use of CO2 is recommended in the process according to the invention. This also advantageously eliminates the need for external procurement and transport of CO2.

[0134] The required amount of CO2 can optionally be extracted from stream 6 by integrating a CCp capture unit 36 ​​into stream 6. The separated CO2 can thus be returned to the gasifier 8 as an optional stream 40 (purge gas stream).

[0135] In the system 50 according to the invention, additional feeds can be provided in addition to the input feeds for the solid CHO fuel, water and oxygen present in conventional gasifiers.

[0136] In particular, the gaseous (educt) streams 17, 23, 24, and 32 indicated in Figure 2 can be provided individually via lances or injected mixed via a single lance, preferably without being premixed with oxygen. The lance(s) (not explicitly marked here) can be positioned as part of the system 50, in particular, in such a way that the fluid dynamics of the fluidized beds typically present in gasifiers 8 are supported.

[0137] The high boilers in mass flow stream 33 are preferably fed via a pump and a lance. Stream 32 can optionally be separated into a gas and a liquid phase in a separator. The gas phase is then fed, for example, with the other gaseous streams 17, 23, and 24 into the gasifier 8, whereas the liquid phase can be fed together with stream 33.

[0138] This phase separation can be useful if, in addition to the lightest hydrocarbons C1 to C4, the naphtha components C5 to C9 are also to be recycled to the gasifier 8 for recycling. This fraction (naphtha) can be recovered as a liquid phase via the aforementioned separator.

[0139] The gasification agents water and oxygen should be continuously fed to the gasifier 8 along with the CHO fuel 5. Ideally, the CHO fuel is gasified with a high concentration of water and a low concentration of oxygen, which can be explained by the following qualitative reaction equations. The previously introduced gasifier equation (3) is composed of the equally qualitative subequations (3a) and (3b):

[0140] Regenerative CHO substances + water + oxygen CO / CO2 / H2 / H2O mixtures (3)

[0141] Regenerative CHO substances + water CO / Hz + little CO2 / HzO / residual CHO substances (3a)

[0142] Regenerative CHO substances + oxygen CO2 / H2O + little CO / H2 / residual CH2O substances (3c) The components CO and H2 (see above) desired in the synthesis gas are formed primarily by gasification with water (cf. equation 3a), while the less favorable components CO2 and H2O are preferably formed by oxidation with O2 (cf. equation 3b).

[0143] However, reaction (3a) is endothermic, while (3b) is strongly exothermic, so that the addition of certain amounts of oxygen is necessary to maintain a minimum gasifier temperature. In order to be able to optimally adjust the mass flows of the gasification agents to be added, water and oxygen, at any time, the gasifier outlet temperature and the CHO concentrations, but at least the CH4 concentration as a characteristic variable, can be measured in stream 6. This is preferably achieved in the form of online measurements, as an embodiment of the invention.

[0144] On the basis of economic considerations, the mass flows of water and oxygen can be determined with the help of the measurement results; they can be easily adjusted using a pump or valve control. If, for example, the CH4 concentration exceeds a threshold value, preferably 1 wt-%, which indicates insufficient conversion, the metered addition of water as the gasification agent can be increased until the conversion has risen so much that the CH4 value falls below, for example, 1 wt-%. If the temperature then falls below a threshold value, preferably 900 °C, due to the now intensified endothermic reaction 3a, the oxygen concentration is increased again until the temperature exceeds 900 °C again.

[0145] In other words, the invention provides the described advantages for processes for producing synthetic hydrocarbons from renewable CHO starting materials using the MeOH synthesis route, particularly through better utilization of the materials and energy introduced into the overall process. The production of renewable starting materials requires high energy and material expenditure due to the electrolysis current for H2 production, the high desorption energy in DAC or carbon capture processes, and the use of only limited biomass in CO or CCp production.

[0146] If the starting material 5 is not burned but gasified, the amount of expensive electrolysis hydrogen required to produce a certain amount of end product, e.g. kerosene, can be reduced by about half.

[0147] If the by-products of the MeOH and HC syntheses are also completely recycled into the gasifier, a further reduction of the amount of H2 by 10 to 15% is possible.

[0148] This is made possible by the described carburetor integration according to the invention, which also brings with it an enormous cost advantage.

[0149] The usability of the gasifier 8 for the utilization of the by-products is made possible by the fact that, according to the invention, suitable dosing devices for liquid and gaseous by-products can be provided (in addition to the solid dosing required anyway for e.g. biomass or waste).

[0150] In the case of complete by-product utilization, the carbon used (apart from small losses caused by a purge exhaust stream) is advantageously found in the main product.

[0151] A main product that can be produced in this way and will be in high demand in the future could be kerosene, for example. If some of the byproducts are also readily marketable, such as renewable diesel or naphtha, these byproducts can be removed separately from the final separation unit of the process and marketed. Other products include unused residual oxygen, which can also be marketed at chemical plants, for example, and a small wastewater stream from the water treatment unit 29.

[0152] Any hydrocarbons or methanol dissolved in the reactant water 2b for the gasifier can be gasified along with the water, so that the carbon contained in it is not lost.

[0153] From an energetic point of view, the decisive advantage is that the energy-rich electrolysis co-product oxygen is used within the overall process according to the invention.

[0154] The heat release resulting from the partial oxidation taking place in the gasifier can be utilized by using the heat for heating purposes at various points in the overall process (see Figure 3 and the heating of material streams and the heating of the evaporators present in the separation columns).

[0155] In addition, the energy-rich synthesis gas produced in the gasifier is converted into methanol or hydrocarbons in subsequent exothermic reactions. The heat released in this process can also be utilized.

[0156] The result is a process whose heat demand is completely covered by its own generation and which can even release excess heat 52 to other processes on site or in the surrounding area. This option is particularly advantageous when it comes to plants in the chemical or pharmaceutical industry or a refinery, into which PtX plants can generally be easily integrated.

[0157] Since heat sinks are always present in such plants, often in the form of evaporation and / or distillation apparatus, excess heat 52 from the PtX process according to the invention can be profitably used.

[0158] An important advantage of the above-described use of electrolysis oxygen over air, which can be used in principle, is that when using O2, no foreign gases such as nitrogen, argon, or potentially formed NOx compounds are introduced into the process. These foreign substances would interfere at various points and necessitate an unnecessary enlargement of all flow-through devices.

[0159] The control of gasifier 8, which is intended to ensure sufficient conversion and the maintenance of a minimum gasifier temperature, is advantageously and simply achieved through a combination of online analysis and O2 / H2O dosing. Online analysis of (at least) the CH4 concentration in the gasifier product stream and measurement of this stream's temperature are sufficient to allow the O2 and water dosing to be adjusted at any time.

[0160] Figure 4 indicates a special embodiment of the gasification operation in the gasifier 8. According to this embodiment, the gasifier 8 comprises a (first) fluidized bed 8a and a further, second fluidized bed 8b or a combustion reactor.

[0161] The fluidized bed 8a and the combustion reactor 8b are coupled via a circulating fluidized bed 39, expediently comprising solid particles (not explicitly marked here), in such a way that a fluidic circuit is created.

[0162] According to one embodiment of the method, step ii) comprises an (endothermic) reaction of the starting material with water vapor 38 in the fluidized bed 8a and a combustion by oxidation with oxygen in the fluidized bed 8b, wherein a corresponding combustion exhaust gas indicated by the reference numeral 37 and resulting from the combustion is reintroduced into the fluidized bed 8a together with the starting material 5.

[0163] In addition, the by-products 17, 23, 24, 32, 33 produced according to the invention can advantageously be made accessible to the combustion mentioned, as can be seen from the schematic process in Figure 4.

[0164] In other words, the gasifier 8 can be designed as a "normal" fluidized bed gasifier. Alternatively, it is also possible according to the invention to provide a "double" fluidized bed as described in Figure 4, in which the processes of conversion with steam (endothermic) and heat generation by oxidation with oxygen are carried out separately. This variant differs from the normal variant in particular in that the by-products can no longer be introduced directly into the gasifier, but into the second fluidized bed, where they are burned with oxygen.

Claims

Patent claims 1. Process for producing hydrocarbons (CH) , comprising the steps: - i) providing a regenerative starting material (5) containing carbon (C) and hydrogen (H), - ii) gasifying the starting material (5) in a gasifier (8), whereby a synthesis gas (6) is produced, - iii) producing methanol (MeOH) from the synthesis gas (6) and regenerative hydrogen (H2), whereby pure methanol (16) is separated from the produced methanol product gas (10), - iv) producing a hydrocarbon from the pure methanol (16), wherein the pure methanol (16) is catalytically converted into a hydrocarbon target product (31), in particular kerosene, gasoline, diesel or naphtha, - wherein by-products (17, 23, 24, 32, 33) of the methanol synthesis and / or the hydrocarbon synthesis are returned to the gasifier (8) and further converted to synthesis gas (6), which is then also converted into methanol and the hydrocarbon product (31).

2. Process according to claim 1, wherein the gasifier (8) comprises a fluidized bed (8a) and a circulating fluidized bed (39), wherein the gasification of the starting material (5) comprises a reaction of the same with water vapor in the fluidized bed (8a) and a combustion with oxygen in the fluidized bed (39) coupled to the fluidized bed (8a), wherein a corresponding combustion exhaust gas (37) from the combustion is introduced into the fluidized bed (8a) together with the starting material (5), and wherein the by-products (17, 23, 24, 32, 33) are made accessible for combustion.

3. Method according to claim 1 or 2, wherein a gasification agent, in particular water (H2O) and / or oxygen (O2), is continuously fed to the gasifier (8) together with the starting material (5).

4. The method according to any one of the preceding claims, wherein the regenerative hydrogen originates from a PEM water electrolysis and is reacted via methanol synthesis together with the synthesis gas (6), wherein a mass flow of the regenerative hydrogen (H2) is selected depending on how much hydrogen is already present in the synthesis gas (6) 5. A process according to claim 4, wherein a portion of the oxygen also produced by electrolysis is fed to the gasification.

6. Process according to one of the preceding claims, wherein the methanol product gas (10) contains foreign gases, water and / or unreacted components of the synthesis gas (6), and wherein liquid or condensed methanol and water components are separated from gases in a separator (15) and these gases are also recycled to the methanol synthesis as cycle gas (12).

7. The method according to claim 6, wherein the condensed components are fed to a distillation (18) in which raw water (7a) and the pure methanol (16) are obtained, wherein the raw water (7a) is fed to a water treatment (29) so that the water can be fed back to the electrolysis and / or to the gasifier (8) as a gasifying agent after purification.

8. Process according to one of the preceding claims, wherein the pure methanol (16) is additionally separated by condensation, wherein existing low boilers (17), in particular methane, remain gaseous and are also fed to the gasification to form synthesis gas (6).

9. The method according to claim 7 or 8, wherein as product (20) of the hydrocarbon production additionally water (7b) which is separated and fed to the water treatment (29), as well as liquid hydrocarbons and gaseous Hydrocarbons are produced, which are returned to the hydrocarbon synthesis as cycle gas (22).

10. The process according to claim 9, wherein the liquid hydrocarbons (21) produced by hydrocarbon synthesis are further fed to a separation column (27) in which further gaseous components (24) are dissolved or separated, which are also fed to the gasification to form synthesis gas (6).

11. Process according to one of the preceding claims, wherein a synthesis gas stream (6) for the methanol synthesis comprises carbon dioxide (CO2), which is removed, for example via a CCy separation (36), and returned to the gasifier (8) as a barrier gas (40).

12. Method according to one of the preceding claims, wherein a methane concentration (CH4) in the synthesis gas stream (6) is measured and monitored as a characteristic variable in order to be able to regulate mass flows of the gasification agents to be added.

13. A process according to any one of the preceding claims, wherein the process can reduce the hydrogen requirement by 50% and, with additional complete utilization of by-products, even by 60 to 70%, in contrast to a hydrocarbon synthesis in which only electrolytically obtained hydrogen is used as a reactant.

14. Synthesis plant (50) , designed to carry out the method according to one of the preceding claims, further comprising the gasifier (8), a methanol reactor (9) and a hydrocarbon synthesis device (CH), wherein the plant further comprises means which allow the by-products of the methanol synthesis (17) and the by-products of the hydrocarbon synthesis (23, 24, 32, 33) to be returned to the gasifier (8) and to synthesis gas (6) which can then be converted into methanol and the hydrocarbon product (31).

15. Plant (50) according to claim 14, further comprising a heat transfer system (51) which is arranged To supply partial steps of the process with heat according to a specific heat requirement, which is provided, in particular completely, by exothermic process steps, wherein the heat transfer system (51) is, for example, a multi-stage steam system and / or a molten salt system.

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